Injustice: Gods Among Us x Reader

The Injustice universe is a universe where Superman descends into villainy following his family's death at the Joker's hands, or more his hands, the story has been written and ended but...this takes place in an alternate Injustice universe. One where (Name) was unknowingly involved. what difference can she make? Who was she to be dragged into this? And...why did their looks...seem so painful?